1. Field
The embodiments discussed herein relate to a CRUM chip and image forming device for authentication and communication and methods thereof, and more particularly, to a Customer Replaceable Unit Monitoring (CRUM) chip and image forming device for authentication and communication for detecting whether data is integral, using integrity detection data in a communication process, and a method thereof.
2. Description of the Related Art
As computers increasingly becoming widespread, the dissemination rate of peripheral devices of computers is also increasing. Computer peripheral devices include image forming devices such as printers, facsimiles, scanners, copy machines, and multi-function printers.
Image forming devices may use ink or toner to print images on paper. Ink or toner is used each time an image forming operation is performed, and thus runs out when used for more than a predetermined period of time. In such a case, the unit in which the ink or toner is stored has to be replaced. Such parts or components which are replaceable in the process of using an image forming device may be defined as consumable units or replaceable units. For convenience of explanation, these will be referred to as consumable units in this document.
In addition to these units which must be replaced due to depletion of ink or toner as discussed above, there are also consumable units having characteristics that change when the units are used for more than a certain period of time, and thus are replaced to achieve a satisfactory printing quality. Consumable units include color replacement for developing machines, and parts such as intermediate transfer belts.
In the case of laser image forming devices, electrification units, intermediate units or settlement units may be used, in which various types of rollers and belts used in each unit may be worn out or degenerated when used for more than the marginal life span. Accordingly, the quality of image may be severely deteriorated. A user must replace each component, that is, each consumable unit at an appropriate replacing period so that printing operation can be performed to produce clean images.
To manage consumable units more efficiently, memories may be attached to consumable units, so as to exchange information with the body of an image forming device.
That is, it is possible to record various usage information such as the number of printed paper, number of output dots, and usage period into the memory of the consumable unit, for management of a time to replace the consumable unit.
As an example, large-scale organizations such as public offices, universities, and enterprises employ Managed Printing Services (MPS) to attempt to manage a plurality of image forming apparatuses with ease. An integrated solution service using MSP may provide the functions of calculating usage fees of consumables for each group or each individual and charging them accordingly and the functions of checking the life spans of consumables and ordering consumables before they wear out. Such functions may be provided based on the exact consumables usage information.
For such information management, a controller provided in the body of an image forming device and a memory unit provided in the consumable unit communicate with each other. However, there are numerous variables in the communication process. For instance, there may be an attack by a hacker who tries to control the controller or the memory unit for malicious purposes.
In addition, there may be a noise interruption caused, for example, by an electronic circuit or a motor provided in an image forming device. Unexpected incidents such as an alien substance getting into a connection part between a main body and a consumable unit of an image forming device, a connection cutting off due to vibration during operations, and/or an electrical interference signal being applied through the connection part, may occur.
Communication data may change due to these variables. For instance, once a job is completed, a consumable unit may transmit information such as the number of printing pages, number of dots, and remaining toner volume to a controller, and copies the information to a nonvolatile memory of the controller. Upon the data being read as an incorrect value, for example, such as 0xFFFFFFFF, there is a risk that the controller may perceive that the life of the pertaining consumable unit has ended. In this case, the consumable unit will not longer be able to be used.
In addition, the consumable unit of an image forming device may have a structure that may be detachable. A memory of a consumable unit is not usually accessed and only the memory of an image forming device is used during a printing operation of the image forming device due, for example, to motor vibration and circuit noise that may occur during the operation. Thus, the communication between the memory of the consumable unit and the image forming device may be performed only in limited occasions, for example, when the consumable unit is mounted on the image forming device so that the memory of the consumable unit and the memory of the image forming device are synchronized with each other, or when the consumable unit is updated for changes after a printing operation is completed and a motor stops.
As there may be a considerable amount of data stored and managed in the consumable unit, various supplementary functions may be required, taking a prolonged communication time. Accordingly, when a consumable unit is replaced during communication, problems may occur. As an example, a consumable usage information of a consumable unit 1 indicates, for example, 100 printing pages, 200 output dots, and 300 motor driving times, and a consumable usage information of a consumable unit 2 indicates, for example, 200 printing pages, 300 output dots, and 400 motor driving times. In this example case, if the consumable unit 1 is mounted on an image forming device, the consumable unit 1 may be synchronized with the memory and data of the image forming device. If the consumable unit 1 is replaced with the consumable unit 2 in the process of synchronization, that is, only the data of 100 printing pages and 200 output dots of the consumable unit 1 is stored in the memory of the image forming device and then, the consumable unit 1 is replaced with the consumable unit 2, authentication may be performed again. Subsequently, the data of 400 motor driving time may be copied to the memory of the image forming device. As a result, the memory of the image forming device indicates, for example, 100 printing pages, 200 output dots, and 400 motor driving times, which are not the correct values. In this example case, if the consumable unit 2 is updated for changes after a printing operation is completed in the image forming device, the data of 100 printing pages and 200 output dots stored in the memory of the image forming device may be stored in the consumable unit 2 while the actual data of the consumable unit 2 indicates 200 printing pages and 300 output dots. As the printing pages become 100 instead of 200, the corresponding consumable unit has incorrect data values and thus, may cause problems.
In addition, an image forming device may have and use a plurality of consumable units in one Inter-Integrated Circuit (I2C) channel, in which case, the consumable units may be categorized by a slave address in the I2C channel. In this case, if a slave address is modified to the ID of another consumable unit due to some temporal problems, wrong data may be stored in the memory of the another consumable unit.
Further, regarding a consumable unit of which the life span has ended, a hacker may attempt to reset the consumable user information, for example, to a value of “0” with a malicious purpose, in order to inappropriately recycle the consumable unit. Accordingly, a user may attempt to use a consumable unit of which the life has ended, causing problems such as breakdown of the image forming device or deterioration of definition, and the user may not be provided with exact information regarding consumable units, and moreover, an integrated solution service may not be available due to the problems of MPS caused by incorrect consumable information.
Accordingly, the necessity for a technology which efficiently detects communication errors between a consumable unit, and an image forming device to seek safety of the data is required.